Electric brake.



No. 830,533. 1 PATENTED SEPT. 11,,190 6-* F. L. SESSIONS.-

ELEOTRIG BRAKE. APPLICATION mum umn, 1 905.

2 SHEETS-SHEET 1.

q/vibmoom PATENTED SEPT; 11, 1906. P. L. SESSIONS. ELECTRIC BRAKE.

APPLIUATION FILED JAN. 17, 1905.

2 BHEETSHEET 2.

WUL (MMLM auoeufoz" T v .UNITED sTATEs PATENT oEEroE.

remain-L. SESSIONS, OF COLUMBUS, Ohio, ASSIGNOR To JosEPEA. JEFFREY, OFCOLUMBUS, orno. v

ELECTRIC BRAKE.

Specification of Letters Patent.

Patented Sept. 11, 1906.

Application filed January 17, 1905. Serial No. 241.525.

To all wit/i121 it may concern: Be it known that I, FRANK L. SESSIONS, acitizen of the United States, residing at C0- lumbus, in the county ofFranklin and State of Ohio, have invented certain new and usefulImprovements in Electric Brakes, of which the following is a.specification, reference being had therein to the accompanying drawlngs.

This invention relates to an improvement in electromagnetically-operatedbrakes for conveyor or elevatorsystems, it being piirtic ulcrly adaptedto prevent the too rapid descent of the elevator or conveyor under theaction of gravity.-

Figure 1 is a side elevation of a conveyor system, provided with a brakeembodying my improvements. Fig. 2 is a plan view of the upper partofsaid system. Fig. 3 is a diagrammatic view of the improvedelectromagnetic brake and the apparatus and wiring of the electricalcircuit.

1 represents a tipple adapted to deliver materialto an elongated endlesscarrier or conveyor 2, which is inclined to the horizon tal and isadapted. to retard the descentunder gravity of the material received byit.

3 is a trough in which the said conveyor operates.

4 represents a shunt-wound motor having the armature 5, the brushes 6 7,and the mo tor field 8.

9 and-10 represent, respectively, the positive and negative conductorsof a source of current-supply.

11 is a double-pole single-throw switch arranged in the electricalcircuit.

. 1.2 is a starting-box having the resistance' controlling lever 12,which is adapted to engage with each of the series ofresistance-controlling contacts 12. 13, 14, and 15 are binding-posts onthe said starting-box.

16 is a conductor leading from one pole of the switch 11 to thebinding-post 13.

17 is a conductor connecting the binding post 13, the current-switchinglever 12, and the binding-post 14 together.

18 is a rheosta-t for controlling the current in the motor field. Oneterminal of this rheostat is connected by theconductor 19 to thebinding-post 14 on the starting-box and the other terminal isconnectedby the conductor 20 to one terminal 8 of the field-coil 8 ofthe motor. The binding-post 15 on the startinghox is connected to oneend of the resistance therein and also to'the brush 6 of the motor. Theother brush 7 of the motor is connected bya conductor 21 to a pole ofthe switch 11. The terminal 8 of the motor field is connected to thesaid conductor 21. It will thus be seen that the field is connecteddirectly across the armature-circuit.

The armature-shaft 5 has a pinion 22 thereon which is adapted to meshwith a bevelpinion 23 on the driving or head shaft 2'- of the conveyer2.

24 is a brake-wheel rigidly secured to the shaft .2. 25 is a brake-bandadapted to en'- gage with the periphery of said wheel, and 26 is a leveradapted to control the action of the said brake-band in the well-knownmanner. This lever is pivotally supported at 26 and has suspended fromits front end a weight 27,

' band tightly to the brake-wheel.

28 is an electromagnet the core 28. of which is pivotally connected tothe outer end of the lever :26. This magnet is arranged to applysufficient force to the said lever to lift it and the wei ht 27, so asto release the brake-band am? permit the revolution of the brake-wheeland shaft 2. Y

The energizing-coil 28 of the brake-lifting magnet 28 is connected byconductor 30 to an electrical contact 31, carried by the starting-box12. This contact is so arranged that the starting-lever 12 will engagewith it prior to its engagement with the first of the series of contacts12. The other end of the magnet-coil 28 is connected by a conductor 32to the energizing-coil 33 of the electromagnet 34, which is adapted tocontrol the operation of the overload-release circuit breaker 35, whichmaybe of any well-known type. consisting of the electromagnet 34, the

- switch-lever 36, the detent for controlling said lever 37, the contact38, with which the said switch is ada ted to engage when in operativeposition, tl ie contact 39, to which said switch-lever is pivotallyconnected, and the spring 40, adapted to cause the disengagement of saidswitch-lever from the contact 38 when the magnet operatesto release thesaid detent.

One end of the ener zing-coil 33 of-the' magnet 34 is connecte to thecontact 38.

For illustration 1 have shown it as The -contact.39 is connected by aconductor 39 to the conductor of the motor field. It will be seen thatthe brake-lifting magnet 28 is connected directly acrossthearmature-circuit and in parallel with the motor field, it having inits circuit an overload-release-circuit breaker. When it is desired tooperate the motor as a motor, current may be applied to it from the line9 thro ugh.the starting-box 12. In view of the fact that theswitching-lever 12 engages with the contact 31 prior to its engagementwith the first of the series of'contacts 12", which controlthe flow ofcurrent to the armature, it will be seen that the magnet-coil 28 will beenergized prior to the energizing of-the armature-coils and that inconsequence the brake-weight 27 'will be elevated by the action of theelectro-..

magnet 28 and the tension on the brake-band released, so that thearmature can be caused to rotate free of the resistance of the brake.

When the motor is being used as a generator-as, for example, when it isbeing used to retard the conveyor I 2the motor being a shunt-woundonean'd the direction of the rotation of the armature being the same aswhen the motor was-driven from a source of current-supply, its field- 8.Will be energized in the same direction as when the motor was supplipdwith current from the main line.' This will insure that thebrake-lifting ma net 28 -will be properly energized, so as to a low theshaft 2" to revolve free of the retarding action of the brake. Shouldthel'oad upon the conveyer 2 become so great as to cause speed, thisincrease of speed of rotation willthe armature 5 to revolve above thedesired develop a suflicient electromotive force to send anexcessivecurr nt through the circuit '1 of the brake-lifting m gnet,with the result that the circuit-breaker will be opened,

breaking the circuit and permitting the when it is running as agenerator. 5

- sary weight'27 to descend under the actiongof gravity'and toimmediately apply the brake applied. It will be understood that numerous modificationsof my proposed manner of operating anelectroma'netcontrol for. a brake mechanism may be devised without de arting formthe spirit of my invention.

hen the motor is operating as a generator,- the current flows from thefield 81 to the rheostat 18, thence to the starting-box 12,

from the contact 31 thereon through the magnet-coils 28" and 33, andthence back to the field. The current through the said energizing-coilsis inthe samedirection that it was v when they" were supplied from thesource of current-supply.

It will'be seen that weight 27 will operate to stop; the rotation of thehead-shaft 2 either when the electromotive force in the circuit of theelectromagnet 28 is greater than the predetermined amount or when it isinsufficient to properly energize the coil 28 of the [said magnet, sothat should the current throu h the system be interrupted in any mannert e weight will at once'operate to stop the motion of the shaft 2.

I claim. 1. The combination with asource of electrical supply and a,shunt-wound motor electrically connected therewith, of a brake connectedwith the armature-shaft of said motor and adapted normally to oppose itsrotation,

an electromagnet for releasing said brake and anelectromagneticallymperated circuitbreaker, the energizing-coils of thebrake-releasing magnet and the circuit-breaker being in series with eachother and connected directly across the current-supply line inparallelwith the armature of the'motor. v

2. The'combination with a source of elec trical supply and a motorelectrically. cohnected therewith, of a brake connected with thearmature-shaft of said motor and adapt.-

ed to normally oppose the rotation thereof,

an electromagnet for releasing said brake, and anelectromagnetically-operated circuitbreaker having its energizing-coilconnected in series with the energizing-coil of said brakereleasinmagnet, the said coil being connected directly across the current-supplyline in parallel with the armature of the motor.

In testimony whereof I aflix my signature in presence of two witnesses.

FRANK L. SESSIONS.

Witnesses:

F. E. VAN SLYKE, C. L. MoCoNKEY.

